[snowwrestler]

The critical factor is weight. Electric heated gloves only work if they have power. Batteries are heavy.

Water and fuel are also heavy, which means climbers on big routes like this are usually riding the edge of starvation and dehydration for days, which further raises the risk of frostbite in extremities.

[Fricken]

There is a lot of stop and go. In the kind of conditions they were in. It's hard not to break a sweat when climbing, and hard to avoid early stage hypothermia when belaying. When the core cools down, blood flow to the extremities is restricted to conserve heat, putting them at risk of frostbite.